My in-laws had a dog named Buster that they originally got as a pup. When the vet saw the dog, he assumed from its coloring that it was a Beagle. So that old hound grew up to the size and strength of a German Shepherd while masquerading as a Beagle.

Although Grampa loved that dog, Buster just couldn't behave. Like the time he chewed a hole in the fence and stuck his head through to bark at the mail carrier.
The carrier took out his mace, and as reported by a neighbor, walked over and sprayed the dog. Zoop, back goes Buster's head through the fence. Off starts the mail carrier to finish his rounds, when, WHAMMMO, out through the shattering boards comes SUPER-BUSTER; HOUND FROM HELL! With foaming froth from the spray all over his snout, Buster chased down and cornered the letter carrier on his jeep top! Then, baying in pain from being sprayed again, off raced Buster to the nearby park where he jumped into the lake.
We later learned that the Dog-pound squad was summoned and tried to fish him out, but he obviously got away and sneaked back home. Luckily the Post Office and Dog Pound didn't realize they were dealing with the same mutt!

That dog never did know his own strength. One time Buster chased a cat under a car and went right on under after it. Unfortunately, Grandpa had tried to keep Buster under control by looping the leash around his wrist and palm and he got pulled halfway under the car too! The neighbors all bit their lips, trying not to laugh, as a greasy, road-tarred man came marching down the street swearing like a sailor! At his side was a hang dog that slinked along not making eye contact with anyone!

Whenever anyone says they have the world's worst dog, I know they don't!
My in-laws had the one and only!

..jfox..